It has been a long known practice to ventilate attics under gable roofs by running a vent along the roof ridge. Such vents are created by an open slot running along the roof ridge, essentially the length of the roof, which causes ventilation out of the attic by convection airflow and by suction from wind blowing across the roof.
A soffit ventilation system is frequently used in conjunction with a ridge vent to provide passive ventilation. The soffit vents allow fresh ambient air to flow into the attic to equalize attic temperature and pressure with the outside. As stale hot air is withdrawn from the ridge slot vent by convection and/or wind suction, it is replaced by fresh ambient air enters the attic through the soffit vents.
Differences between the various types of ridge vents are often found in the capping structures used over the vent slot to exclude water and pests. A description of representative types of ridge vents and capping structures, and attributes or problems associated with various types, is found in a prior patent of this inventor, U.S. Pat. No. 5,167,579 (Rotter). That patent discloses, as a solution to many of the problems associated with prior ridge vents, an improved roof ridge venting system using a unitary mat constructed of randomly-aligned synthetic fibers which are joined by phenolic or latex binding agents and heat cured to provide an air-permeable mat with a varying mesh. Cap shingles are supported by the mat and are nailed directly to the roof through the mat. In contrast to other vent materials, the unique features of the mat disclosed in the Rotter patent result in many desirable physical properties such as high tensile strength, high resiliency, the ability to be transported in rolls and cut to length, ease of joining strips, durability in local ambient conditions, and an excellent water and insect barrier. Moreover, it provides the aforementioned desirable features in a thin sheet to permit the vent structure to maintain a low profile along the roof.
Although the vent disclosed in the Rotter patent has desirable applications in many roof types, some of its advantages begin to diminish when it is used in conjunction with heavy roofing tiles. As used herein, the phrase "heavy roofing tiles" refers to tiles made from materials which include, but are not limited to, slate, terra cotta, concrete, and clay. These tiles are distinguished by their bulk and weight, as contrasted to the relatively lighter shingles made of asphalt, wood, fiberglass, polymers and the like.
A vent structure useable with such heavy roofing tiles should not only retain its desirable features set out above, it must be able to support and anchor the capping elements, which are frequently heavy ridge tiles of same or similar shape and construction as the roof tiles, and must retain them in position even in high wind and other adverse environmental conditions such as temperature extremes and the accumulation of heavy layers of snow or ice. A recently developed reinforced vent matting for this purpose is disclosed in PCT published application number US92/06658 (also Rotter). In one embodiment of the Rotter PCT application, the unitary matting of randomly-aligned synthetic fibers includes a grid pattern of small reinforcing pins extending perpendicularly through the thickness of the mat. These reinforcing pins are designed to support heavy roof ridge tiles without significantly hampering airflow through the vent matting.
Notwithstanding the availability of using the pin-reinforced vent matting disclosed in the Rotter PCT application in a ridge vent for heavy roofing tiles, this invention is directed to a novel roof ridge ventilation system which is designed to support and anchor heavy ridge tiles, and to the method of venting such tiled roofs with this novel system. In particular, it is designed for typical terra cotta tile roofs, wherein the tiles have a nearly semi-circular section profile, and are laid in rows alternatingly inverted and overlapped with the preceding row to form an undulating sequence of crests and gutters. The same or similar shaped tiles are then laid along the ridge to cap the slot and to impart a rounded appearance to the ridge.
In prior construction using only basic building materials, a wood beam or "ridge pole" was installed in the slot to anchor and support the capping tiles, which were nailed to the top edge of the beam. In some instances guide rods were used where the nails were not sufficient to anchor the capping tiles, as shown in U.S. Pat. No. 2,214,183 (Seymour). Strips of sheet metal were sometimes bent at an angle and tacked to the sheeting adjacent the slot on each side to extend under the cap and act as a baffle deflector of wind-driven rain and debris, or specially constructed shingles could be used for the same effect (see element 6 in Seymour). To inhibit pests, a screen may have been laid across the slot under the ridge pole, or draped over the ridge pole and tacked to the sheathing, or contoured under the capping tile (see element 16 in Seymour).
One attempt to provide an improved structure for supporting such capping tiles is disclosed in U.S. Pat. No. 4,558,637 (Mason). The apparatus disclosed in Mason uses a support member with a center anchoring crest for nailing the tiles thereto and longitudinal upright side portions to support edges of the tiles. Vent openings in the side portions and in the shield portions connect the sides to the crest.
None of the above described devices includes an air-permeable vent material, nor appears to be readily adjustable in height, nor is assembled from easily handled components.
One objective, therefore, is to provide a roof ridge ventilator which is designed for use with heavy roofing tiles and which includes an air-permeable vent material as a water and insect barrier. Another object is to provide the capability to adjust the height of this roof ridge ventilator to accommodate various shapes and heights of tile. A further object is to provide components of the ventilating system in convenient and easy to handle forms such as rolls and sheets, and to provide a convenient method of assembling and installing the ventilation system on roofs of different lengths and slope. These and other objects are achieved through the novel roof ridge ventilation system described below.